iswasmfast VS scope_guard

At a glance, the bindings for wasm copy the data,

https://github.com/zandaqo/iswasmfast/blob/54bbb7b539c127185...

If the running code is short enough then that copy might easily make the wasm version much slower. That is indeed a known downside of wasm (calls to JS are somewhat slow, and copying of data even more so - wasm shines when you can avoid those things).

If it's not that, then a 10x difference suggests you are running into some kind of a VM bug or limitation.

WASM has its moments, as you can see in this[1] benchmark it outperforms JS and native addons on certain tasks.

Since the bottleneck with native addons is usually data copying/marshalling, and we have direct access to WebAssembly memory from the JavaScript side, using WebAssembly on this "shared" memory might become the best approach for computationally heavy tasks. I wrote about it a bit here[2].

[1] https://github.com/zandaqo/iswasmfast

A few years ago I did similar comparison but in context of Node.js and sans manual optimizations: https://github.com/zandaqo/iswasmfast

In my work, I have come to conclusion that it seldom pays off to go "native" when working with Node.js. More often than not, rewriting some computationally heavy code in C and sticking it as a native module yielded marginally better results when compared with properly optimized js code. Though, that doesn't negate other advantages of using said technologies: predictable performance from the start and re-using existing code base.

E.g. see this implementation: https://ricab.github.io/scope_guard/

But also I should make the point that you generally don't need to write defer-like statements at all when using RAII because it's implemented in the actual type. So it's only more code overall for types that are used only once or maybe twice.

Meanwhile I will check and use https://github.com/ricab/scope_guard

> low level details leak into your high level description of code, making the two coupled. You can’t make them invisible.

It's your job to make it not to leak. You have to write Modern C++ wrappers around C libs.

Similarity, The same can be said for Java. You can do low level in Java.

C++ is not C. C++ has backward compatibility with C.

Look at Boost folks, they wrote a Modern C++ wrapper around a C HTTP parser.

> And as I said, I’m familiar with RAII, it’s really great when the given object is scope-based, but can’t do anything otherwise.

Nothing is impossible.

You can use Scope Exit Guard with QT Widget.

https://github.com/ricab/scope_guard

> And if the new subclass has some non-standard object life cycle you HAVE to handle that case somewhere else, modifying another aspect of the code. It is not invisible, unless you want leaking code/memory corruption.

Again, Scope Exit Guards solve your problem!